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LS-DYNA

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Full Feature List

Analysis Capabilities

LS-DYNA is a multi-purpose, explicit and implicit finite element program used to analyze linear and nonlinear static and dynamic behavior of physical procedures. The main capabilities of LS-DYNA are

  • Nonlinear Dynamics
  • Parallel Processing (SMP, MPP)
  • Explicit and Implicit Time-Stepping
  • Eigenvalue Analysis
  • Adaptive Mesh Refinement
  • Thermal Analysis
  • Fluid Dynamics
  • Arbitrary Lagrangian-Eulerian (ALE)
  • Fluid-Structure Interaction
  • Failure Analysis
  • Crack Propagation
  • Fully Automated Contact Analysis
  • Quasi-Static Simulations
  • FEM to Rigid Multi-Body Dynamics Coupling
  • Real-Time Acoustics
  • Multi-Physics Coupling (structural, thermal fluid, acoustics, etc.)
  • Smooth Particle Hydrodynamics (SPH)

 

Element Library

The lower-order finite elements in LS-DYNA are accurate, simple and efficient. For the under-integrated shell and solid elements, zero-energy modes are controlled by either an hourglass viscosity or stiffness. All elements are nearly 100% vectorized.

Beams
- Hughes-Liu Beam
- Belytschko-Schwer Resultant Beam
- Truss Element
- Belytschko-Schwer Beam with full cross-section integration
- Belytschko-Schwer Tubular Beam
- Discrete Beam / Cable
- 2D Plane Strain Shell Element
- 2D Axisymmetric Volume Weighted Shell Element
- Spotweld Beam

Discrete Elements
- Spring (translational and torsional)
- Damper (translational and torsional)

Seatbelt Elements
- Accelerometer
- Pretensioner
- Retractor
- Sensor
- Slipring

4-Node Thin Shells
- Hughes-Liu Shell
- Belytschko-Tsay Shell
- Belytschko-Leviathan Shell
- Belytschko-Wong-Chiang Shell
- Fully Integrated Shells
- Plane Stress Shell
- Plane Strain Shell

Triangular Shells
- C0 Shell
- DKT Shell

Membranes
- Belytschko-Tsay Membrane
- Fully Integrated Belytschko-Tsay Membrane

Solids
- 8-Node Brick Element
- 4-Node Tetrahedron Element
- Arbitrary Lagrangian-Eulerian (ALE) Brick Element
- Eulerian Brick Element
- Eulerian Navier-Stokes Element

8-Node Thick Shells
- Reduced Integration
- Selective Reduced Integration

Material Models

LS-DYNA has over 130 metallic and non-metallic material models.

  • Elastic
  • Elasto-Viscoplastic
  • Elastomers
  • Foam Models
  • Linear Visco-Elasticity
  • Glass Models
  • Geological Models
  • Fabric Material/Element
  • Kevlar Material with Damage
  • Equations-of-State Hydrodynamic Models
  • Acoustic Pressure Material/Element
  • Biomechanic Material Models
  • Composites
  • Special Capabilities for Fluid Analysis
  • User-Defined Materials

 

Contact

The fully automated contact analysis capability in LS-DYNA is easy to use, robust, and validated. It uses constraint and penalty methods to satisfy contact conditions. These techniques have worked extremely well over the past twenty years in numerous applications such as full-car crashworthiness studies, system/component analysis, and occupant safety analysis. Coupled thermo-mechanical contact can also be handled.

Over fourty different contact options are available. These options primarily treat contact of: deformable to deformable bodies, single surface contact in deformable bodies, and deformable body to rigid body contact. Multiple definitions of contact surfaces are possible, for example:

  • Singel Surface Contact
  • Contact with Rigid Walls
  • Tied Surfaces
  • Nodes Tied to Surfaces
  • Shell Edges Tied to Shell Surfaces
  • Fluid-Structure Interfaces
  • Eroding Contact
  • Edge-to-Edge Contact
  • Resultant Force Contact
  • Draw Beads
  • Contact with CAD Surfaces

A special option exists for treating contact between a rigid surface (usually defined as an analytical surface) and a deformable structure. On example is in metal forming, where the punch and die surface geometries can be input as IGES- or VDA-surfaces which are assumed rigid. Another example is in occupant modeling, where the rigid-body occupant dummy (made up of geometric surfaces) contacts deformable structures such as airbags and instrument panels.

Several friction models are available:

  • Static and Dynamic Coulomb Friction
  • Viscous Friction
  • Pressure Dependent Friction
  • User-Defined Friction Models

Contact input is made easier by allowing contact to be defined by part identifiers, by box, or by simply including the entire model in the contact definition.

Specialized Automotive Features
  • Seat-Belts - including modeling of accelerometer, pre-tensioner, retractor, sensor, and slip ring
  • Inflator Models
  • Airbag Fabric Constitutive Models
  • Accelerometers
  • Airbag Sensors
  • Airbag Breakout
  • Eulerian Deployment of Airbags
  • Airbag Folder
  • Unfolded Reference Geometry for Airbags
  • Dummy Positioner
  • Side-Impact Dummy Special Damper
  • Airbag Stitched Interface Model/Straps

 

Specialized Metal Forming Features
  • Anisotropic Strain Rate Dependent Plasticity
  • Rigid Tooling
  • Specific Contact Options
  • Thermal Contact
  • Automatic Segment Orientation
  • Coupled Thermal/Mechanical Analysis
  • Multi Stage Tooling
  • Implicit Springback
  • Trimming (Shell Elements Only)
  • Arbitrary Langrangian-Eulerian Formulation
  • Adaptive Mesh Refinement
  • Element Deletion due to Element Failure
  • Rigid Body Stoppers for Tool Control
  • Pressure via Load Mask (Hydroforming)

 

Adaptivity

Automatic re-meshing permits the user to achieve accurate results at minimum cost:

  • Adaptive Options
  • Error Norms
  • User-Specified Refinement Levels
  • Sub-Cycling
  • Graphical Output

 

Rigid Body Dynamics

LS-DYNA provides many capabilities to perform simulations using multi body dynamics. The main features are:

  • Spherical and Revolute Joints
  • Cylindrical
  • Planar
  • Universal
  • Translational
  • Locking
  • Translational and Rotational Motor
  • Gear
  • Rack and Pinion
  • Pulley
  • Screw
  • Cardan Joint
  • Switching Rigid to Deformable Material
  • Rigid Body Stoppers
  • Rigid Body Contact

 

Functionality

A variety of controls, options, and subroutines permit the user to have maximum flexibility in defining the simulation problems:

  • Keyword Input
  • Direct Input of Nastran Bulk Data Files
  • Splitting of Input File into Subfiles
  • User Subroutines
  • Re-Mapping
  • General Restarts
  • Transmitting Boundaries
  • Dynamic Storage Allocation
  • Data Base Output Controls
  • Sense Switch Controls - Monitor Simulations Status
  • Dynamic Relaxation
  • Interactive Real-Time Graphics
  • Pre-Stressing from Nastran Linear Solution
  • Double Precision for 32-Bit Workstations
  • Optimization

 

Validation

LS-DYNA simulation results have been consistently correlated with experimental data at various customer sites. These extensive tests give the user high confidence in using the program as an accurate simulation tool. Before each release, the program is subjected to rigorous quality assurance testing which consists of over 300 test problems.

Computers

LS-DYNA runs on leading PCs, Unix workstations, supercomputers, and MPP (massive parallel processing) machines. Computer resource requirements vary depending on problem size. Simulations with more than 100,000 elements have been run using 15 million words of memory and 100 Mbytes of disk space. On super-computers, the code is highly vectorized and takes advantage of multiple processors.